If I am to judge solely from your original post, I would suggest that you do not yet have the technical knowledge or business acumen to be successful in this type business, or to even begin it.
My suggestion is that you appear to be at the point of needing to start with education in both the home automation field and in the business world. Without those two things under control, you would be quickly on the road to failure.
When you're ready, you'll not only know the answers to the questions you posed, but you'll know the answers to a number of others you haven't asked.